6.6-stable review patch. If anyone has any objections, please let me know.
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From: Li Zhijian lizhijian@fujitsu.com
[ Upstream commit 62c2aa6b1f565d2fc1ec11a6e9e8336ce37a6426 ]
scan_labels() leaks memory when label scanning fails and it falls back to just creating a default "seed" namespace for userspace to configure. Root can force the kernel to leak memory.
Allocate the minimum resources unconditionally and release them when unneeded to avoid the memory leak.
A kmemleak reports: unreferenced object 0xffff88800dda1980 (size 16): comm "kworker/u10:5", pid 69, jiffies 4294671781 hex dump (first 16 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace (crc 0): [<00000000c5dea560>] __kmalloc+0x32c/0x470 [<000000009ed43c83>] nd_region_register_namespaces+0x6fb/0x1120 [libnvdimm] [<000000000e07a65c>] nd_region_probe+0xfe/0x210 [libnvdimm] [<000000007b79ce5f>] nvdimm_bus_probe+0x7a/0x1e0 [libnvdimm] [<00000000a5f3da2e>] really_probe+0xc6/0x390 [<00000000129e2a69>] __driver_probe_device+0x78/0x150 [<000000002dfed28b>] driver_probe_device+0x1e/0x90 [<00000000e7048de2>] __device_attach_driver+0x85/0x110 [<0000000032dca295>] bus_for_each_drv+0x85/0xe0 [<00000000391c5a7d>] __device_attach+0xbe/0x1e0 [<0000000026dabec0>] bus_probe_device+0x94/0xb0 [<00000000c590d936>] device_add+0x656/0x870 [<000000003d69bfaa>] nd_async_device_register+0xe/0x50 [libnvdimm] [<000000003f4c52a4>] async_run_entry_fn+0x2e/0x110 [<00000000e201f4b0>] process_one_work+0x1ee/0x600 [<000000006d90d5a9>] worker_thread+0x183/0x350
Cc: Dave Jiang dave.jiang@intel.com Cc: Ira Weiny ira.weiny@intel.com Fixes: 1b40e09a1232 ("libnvdimm: blk labels and namespace instantiation") Suggested-by: Dan Williams dan.j.williams@intel.com Signed-off-by: Li Zhijian lizhijian@fujitsu.com Reviewed-by: Dan Williams dan.j.williams@intel.com Reviewed-by: Ira Weiny ira.weiny@intel.com Link: https://patch.msgid.link/20240819062045.1481298-1-lizhijian@fujitsu.com Signed-off-by: Ira Weiny ira.weiny@intel.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/nvdimm/namespace_devs.c | 34 ++++++++++++++++----------------- 1 file changed, 17 insertions(+), 17 deletions(-)
diff --git a/drivers/nvdimm/namespace_devs.c b/drivers/nvdimm/namespace_devs.c index 07177eadc56e8..1ea8c27e8874d 100644 --- a/drivers/nvdimm/namespace_devs.c +++ b/drivers/nvdimm/namespace_devs.c @@ -1927,12 +1927,16 @@ static int cmp_dpa(const void *a, const void *b) static struct device **scan_labels(struct nd_region *nd_region) { int i, count = 0; - struct device *dev, **devs = NULL; + struct device *dev, **devs; struct nd_label_ent *label_ent, *e; struct nd_mapping *nd_mapping = &nd_region->mapping[0]; struct nvdimm_drvdata *ndd = to_ndd(nd_mapping); resource_size_t map_end = nd_mapping->start + nd_mapping->size - 1;
+ devs = kcalloc(2, sizeof(dev), GFP_KERNEL); + if (!devs) + return NULL; + /* "safe" because create_namespace_pmem() might list_move() label_ent */ list_for_each_entry_safe(label_ent, e, &nd_mapping->labels, list) { struct nd_namespace_label *nd_label = label_ent->label; @@ -1951,12 +1955,14 @@ static struct device **scan_labels(struct nd_region *nd_region) goto err; if (i < count) continue; - __devs = kcalloc(count + 2, sizeof(dev), GFP_KERNEL); - if (!__devs) - goto err; - memcpy(__devs, devs, sizeof(dev) * count); - kfree(devs); - devs = __devs; + if (count) { + __devs = kcalloc(count + 2, sizeof(dev), GFP_KERNEL); + if (!__devs) + goto err; + memcpy(__devs, devs, sizeof(dev) * count); + kfree(devs); + devs = __devs; + }
dev = create_namespace_pmem(nd_region, nd_mapping, nd_label); if (IS_ERR(dev)) { @@ -1983,11 +1989,6 @@ static struct device **scan_labels(struct nd_region *nd_region)
/* Publish a zero-sized namespace for userspace to configure. */ nd_mapping_free_labels(nd_mapping); - - devs = kcalloc(2, sizeof(dev), GFP_KERNEL); - if (!devs) - goto err; - nspm = kzalloc(sizeof(*nspm), GFP_KERNEL); if (!nspm) goto err; @@ -2026,11 +2027,10 @@ static struct device **scan_labels(struct nd_region *nd_region) return devs;
err: - if (devs) { - for (i = 0; devs[i]; i++) - namespace_pmem_release(devs[i]); - kfree(devs); - } + for (i = 0; devs[i]; i++) + namespace_pmem_release(devs[i]); + kfree(devs); + return NULL; }